I'm guessing OP has some sort of familiarity with Daniels. I tend to follow his recommendation of keeping vo2max-type intervals to 5 minutes or under. I don't think that needs to be a hard, fast rule, but I find we can get good enough workouts starting with 600s and building toward 1200s. Sometimes we don't go above 1000s for race pace workouts, depending on how many weeks without races we have.
One important note is that 100% vo2max pace is around 3200 pace. For some of the slower runners, it might be closer to 1600 pace. That means you can go a bit longer at 5k pace than Daniels would say you can go for a vo2max workout.
In short, it's not something I would do, but I don't think it's inherently stupid. My runners are doing 1k-2k tempos intervals and 600s at race pace this time of year. Other coaches do other things and get results, though.